Its not based on what is most common or easiest to find. You have to match your arrow and your bow. Most of the time you can get by with adjusting your bow weight or point weight to correct a weak/stiff spine.

If your arrow is too weak...decrease poundage or point weight or get a stiffer arrow. If too stiff, increase poundage or point weight or get a weaker arrow. It really just depends.

Tomorrow when I get home I'll run your setup through On Target 2, a program that can firgure all this out the easy way.